Joe Whitty believed prison walls should be permeable. Photograph: David Sillitoe for the Guardian

Joe Whitty, who has died aged 79 after suffering from progressive supranuclear palsy (PSP), was highly regarded as a reforming prison governor both by prisoners and by those seeking to improve the system. His profile was highest from 1989, when he became governor of the troubled Feltham Young Offender Institution in Hounslow, west London. He frequently found himself at odds with the Conservative government.

Called to deal with the suicide of a 20-year-old who had hanged himself because, as he explained in his note, "I am freezing cold and haven't got a book to read," Whitty had to ask himself, "what system am I part of?" He installed CCTV to monitor assaults, and when the Home Office refused to foot the bill, said he would put the cost on his credit card.

He believed – as did his fellow governor Andrew Coyle, now emeritus professor of prisons at King's College London – that prison walls should be permeable. "He set up the Friends of Feltham," recalled Coyle "and also an internal radio service for the prisoners, which was not just for entertainment but was educational."

Whitty took a group of Feltham prisoners to a three-day conference organised by the Howard League for Penal Reform. In the more salubrious confines of an Oxford college, the youngsters mingled with barristers, magistrates and even the home secretary, David Waddington. "He was a lovely troublemaker," recalled Frances Crook, the league's chief executive. "He let in prison reform groups like ourselves and let the kids out. As soon as they were sentenced by the courts, he would get them back out into the community. While he was in charge at Feltham, the number of 15-year-olds in custody across the country was reduced to 20. He was straight and brave and put the welfare of difficult and unpopular people at the heart of what he did."

But he was never a soft-centred liberal and could be tough when necessary. "He was often called a maverick," said Coyle "but that description fails to recognise the sophistication with which he managed prisons, and his firm leadership." Whitty also had, as Nick Davies pointed out in the Guardian, "an almost reckless indifference to diplomacy".

His approach may well have been determined by being brought up in poor Irish Catholic household in Liverpool. A highly intelligent child, he won a scholarship to the local grammar school, but feeling inadequate compared with his wealthier schoolmates, he underachieved and left with no qualifications.

By then a recalcitrant youth, he took a job in the docks. He rejected parental advice not to join the Royal Navy and signed up for seven years. By the time he came out, he was an alcoholic who had repeatedly faced disciplinary charges – though he was also a rugby star for the RN and the London Irish teams.

He briefly emigrated to Canada. There he found a job as a prison officer and a regime that embraced therapeutic ideas and the belief that prisoners could be changed and reformed. On his return to Britain in 1961, he hoped to put these principles into practice.

After a spell at HMP Blundeston, near Lowestoft, Suffolk, he worked his way through the system, becoming deputy governor at Gartree, in Market Harborough, Leicestershire in the mid-1970s. There, he encountered many of the most notable criminals of the day, though wherever he went the prisoners came to trust him. As governor of the Askham Grange women's prison, North Yorkshire (1980-82), he tried to restore the self-respect of the women by involving them in the local community. The prisoners threw a party for him when he left. "We're all heartbroken he's going." said one, "he's the best governor anyone can remember anywhere."

As governor of Long Lartin, near Evesham, Worcestershire, from 1986 he encountered the high-profile criminal Charles Bronson, who described him as "a legend". Then he was asked to sort out Feltham.

He had to steer a difficult course between the rock of Home Office bureaucracy and the hard place of the Prison Officers' Association. He found out that prison officers were drinking heavily in the bar during the evening and then roughing up the inmates. One officer on escort duties would get so drunk that roles were reversed and the prisoners had to bring him back.

He tried to make the system more open and accountable. "His dedication to the ideal of rebuilding damaged human beings, whether young offenders or murderers," wrote Robin Lustig in the Guardian in 1990, "is something our prison system desperately needs." However, since Whitty retired in 1994, successive British governments have retreated to the warehousing approach that he so abhorred.

After he left the prison service, he worked for a private company running prisons and also for the Heathrow airport immigration centre.

He and his wife, Mary, whom he married in 1957, were keen on physical fitness and regularly ran marathons for charity until his illness intervened. He is survived by her, his son, Richard, and grandchildren, Joanne and Adam.

• Joseph Whitty, prison governor, born 11 May 1934; died 13 August 2013